Protective device for safe time clocks



July 7, 1 25'. 1,545,431

D. C. JANNOPOULO PROTECTIVE DEVICE FOR SAFE TIME CLOCKS Filed lla y 14, 1924 Patented July 7, 1925.

* UNITED s'rArss 1,545,431 PATENT orrlca.

DEMOSTHENES C. JANNOPOULO, OF ST. LOUIS, MISSOURI.

a, PROTECTIVE DEVICE FOR SAFE TIME CLOCKS.

Application filed May 14, 1924. Serial No. 713,232.

To all whom it may concern:

Be it known that DEMOSTHENES 0. JAN- NOPOULO, a citizen of the United States, residing at St. Louis, State of Missouri, has invented certain new and useful Improvements in Protective-Devices for Safe Time Clocks, of which the following is a specification.

This invention is in the way of a protective device for the time clocks of safes and vaults. 'It is a well known fact that the usual or standard time clocks may be speeded up by projecting a magnetic field angularly or obliquely across the clock mechanism, which results in accelerating the oscillations of the balance wheel.

It is the object of the present invention, therefore, to supply a relatively simple and yet effective braking device which may be readily mounted in connection with any standard time clock and which will operate to prevent the stated acceleration of the balance wheel thereof.

In the drawing Figure 1 is a perspective view of the balance wheel of a time clock with this device operatively positioned in relation thereto; f

I Figure 2 is' a side View of the assembly shown in Figure 1;

Figure 3 is a top or plan view;

Figure 4' is a transverse sectional view through a portion of the balance wheel and through the braking mechanism.

This improvement is designed for use upon a conventional chronometer' or time clock. Such a time clock includes a balance wheel 1 having a cross bar 2 whereby it is pivoted at 3 to the bracket 4 which supports the wheel within the clock frame (not shown) and in operative position relative to the rest of the clock mechanism (not shown).

In carrying out this invention there is pivoted at 5, in close proximity to the balance wheel 1, a composite metal bar 6, which is made up ofa thin strip of brass 7 havinga thin strip of steel 8 mounted upon one end thereof. The bar 6 is nicely balanced upon its pivot points 5, and is preferably, though not necessarily, slightly bowed or bent at its center point 9, for a purpose to be later explained. A pivot pin 10 is secured transversely to the bar 6 at the center oint 9, and the ends of this pin have pivotal bearings at the points 5 in the bracket 11, as stated, and the bracket 11 is in turn secured to the clock frame or case, in any conventional manner (not shown).

It will be noted that the axis of the pivot pin 10 is mounted obliquely relative to the plane of the balance wheel 1, as clearly shown in Figure 4. At each end of the bar 6 is mounted an angular rubber stop 12, adapted to frictionally impinge upon the periphery of the said balance wheel as either end of the bar 6 is tilted obliquely down toward the wheel under the influence of magnetism. The bar 6 is mounted to move easily in its bearings 5, so as to turn even in a weak magnetic field, and a delicate coil spring 13 is set over one end of the pin 10 with one end attached to the pin and the other end to the bracket 11, and serves to normally hold the bar 6 out of engagement with the balance wheel 1.

The operation of the device is as follows: A magnetic field, when thrown in the region of the balance wheel 1, acts upon the steel strip 8 at one end of the bar 6, thereby causing the bar 6 to turn in its bearings until one of the frictional stops or shoes 12 strikes upon the periphery of the balance wheel 1 and retards the oscillation of that wheel. At the same time the said magnetic field tends to speed up the oscillations of the balance wheel, above its normal rate. Therefore, the pivoted bar 6 acts either as a governor to keep the wheel going at its normal rate, when a magnetic field is directed upon it, or to reduce the balance Wheel to an abnormally slow rate of oscillation, thereby frustrating any unauthorized attempts to speed it up abnormally by the use of magnetism. The coil spring 13 acts to hold the bar 6 in a normal inoperative position and until the influence of a magnetic field is brought to bear upon it. The bar 6 is bowed as stated, and is positioned askew relative to the plane of the balance wheel, in order to render it even more difficult to influence the speed of the balance wheel by means of magnetism, without at the same time setting in operation the preventive agency of the bar 6 to counteract any accelerating effect of a magnetic field thrown across the clock. The reason for this is that a magnetic field must be thrown obliquely across the balance wheel in order to accelerate its motion, while the bar 6, having the susceptible steel strip 8 at one end thereof, is influenced Whether the lines of fence s t 'i ke it ei ther pe'fpntl-icu'la gly 611" oblique'lyf By mou'iiting"'tlie"ba"'r "6 at ail angle relative to the Wheel 1, the1ef0're,'it

6 is thought that the idifiiculty oif'iian' une authorized attempt at speeding the balance Wheel is increased. 175757? E3 While I have herein described a. certain specific manner and method'ofconstfuctiifg and as e blin th l men s 9f my n: Yeme i ii s tofqd li ay 115 m jd-ta l ffom' the spiritof invention, "so

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stops mounted upon the ends of the bar a iii r' qfp fima flii" h s psf fih y;

coil spfing set in tiie"piiidtali1f1ount- 'ing ofthe said bar and adapted to hold the bar normallyin" inoperative. position.

In combination with a time clock and the balance"'ii hel iliereof, the said Wheel being susceptible to magnetic acceleration, (so deviceto"pi eveiit such acceleration, the Same comprisilsg an rwa e b r p voted by its center vtb tui" infiaplglpef qbliq' being susceptible to acceleifa on, 85 a dev ce to preyent s uc h c' el'e'r'at n the sainejcompr sin'gan aif'c'uatfe ar'ipi" planeof the w v'li'efand s0"that' its turn will impingeuthe peripheryflf {the Wheehthe's aidbar being cfginfpqfsedfo-f magnetic material at one ef dfafid of netic mater" 'Y bf 1 h? i haixbsins pr vid 'shoes' adapted 5 ,liear'i upon i thl zbahiic t. 9 1

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